Endstop members for slide fasteners



Dec. 9, 1969 A. FROHLICH ENDSTOP MEMBERS FOR SLIDE FASTENERS Filed Nov. 5, 1966 A APO/V5 F RGWL/CH 1N VENTOR Attorney United States Patent Int. Cl. A44b 19/36 US. Cl. 24-20511 2 Claims ABSTRACT OF THE DISCLOSURE This disclosure is directed to slide fasteners whose endstop members are integrally molded from syntheticresin foil overlying the respective tapes but extending only partly across the latter to facilitate attachment of the slide fastener to a fabric and prevent irritation to a wearer.

My present invention relates to improved endstop members for open-end (separable) or closed slide fasteners.

In my copending application Ser. No. 473,002, filed July 19, 1965 (now US. Patent 3,353,233), I disclose and claim improvements in slide-fastener strips wherein a pair of slide-fastener halves, each having a respective support band or tape and a respective fastener element extending along an edge of the band while being matingly couplable with the fastener element of the other band upon the shifting of a silder along these elements in a fastener-closing direction, is provided with endstop members of a thermoplastic material afiixed to the strip at least at one end thereof by thermal fusion for blocking withdrawal of the slider from the strip and/or facilitating insertion of a strip-fastener element into the appropriate channel of the slider. According to that application and the commonly assigned copending applications Ser. Nos. 472,953 (US. Patent No. 3,353,256) and 473,003 (U.S. Patent No. 3,340,594) of July 19, 1965 and Ser. Nos. 562,877 and 566,413 of July 5, 1966 and July 19, 1966, respectively, the endstop formations which facilitate the guiding of the slider into the fastener element or which subsequently block withdrawal of the slider are integrally molded from the material of the reinforcing strip upon or concurrently with its fusion to the band. As pointed out in those applications, the fastener elements themselves may be composed of a thermoplastic material and constituted as part of the endstop members by fusion and molding concurrently with the latter. Thus the fastener element (which may be a molecularly-riented polyamide monofilament coil in a helical configuration designed for interengagement of its turns with those of a like coil, with or without matingly engageable heads, or a train of individual and spaced-apart coupling members engageable between the corresponding members of the other slide-fastener half, or any other coupling element commonly used in the slide-fastener art) contributes synthetic-resin thermoplastic material to the moldable mass transformed into the endstop member.

Furthermore, the aforementioned applications point out that an important advantage in such systems derives from the fact that the reinforcing strip constitutes a stiffening member at the extremities of the slide fastener so that the user can grip the spreadable end of a separable slide-fastener strip and more easily insert one of the coupling elements into the slider. In fact, applications Ser. Nos. 562,877 and 566,413 are directed specifically to a unique arrangement whereby the moldable ice strip also forms an end stiffener preventing unraveling of the tape, is resistant to washing in aqueous media and treatment by organic solvents, and prevents tearing of a guide portion of an endstop member from the tape upon repeated insertion of this guide portion into the slider.

In general, moldable reinforcing strips of this character were produced according to prior developments by me and my coworkers, as set forth in the abovementioned applications, by juxtaposing a length of reinforcing strip (e.g., a thermoplastic foil) with a continuous slide-fastener strip and making that reinforcing strip of a length equal substantially to the width of the continuous strip. Thereafter, the length of reinforcing foil is applied to the slide-fastener band with heat and pressure over the entire breadth of the band (e.g., with a stamping and forming die and inductive heating), to bond the foil to the substrate strip and concurrently to shape endstop formations in the heated portion of the strip. Subsequently, individual lengths of slide fasteners are severed along the respective reinforcing foils so that each application of such a foil forms the lower endstop members of one length of slide fastener and the upper endstop members of a successive slide-fastener length.

While the aforedescribed system has been found to be wholly advantageous and eflicient and the resulting slide fasteners represent a vast improvement over prior developments in this field, several problems have arisen with respect to the reinforced portion of these slide fasteners. Firstly, the reinforcing foil at the opposite ends of these slide fasteners spans the entire width thereof and so stitfens the support tapes even at their sides remote from the coupling elements as to preclude their permanent fastening to a garment or other body in which the slide fastener is mounted. Not only do the fastening threads tend to loosen because of the stiffness of the foil, but this very stiffness causes thread breakage when attempts are made to attach the slide fastener to a garment by a conventional sewing machine. As a consequence, the reinforced end of the slide fastener tends to be attached less securely to the adjoining support portion and may lead-to defects in the garment. Another disadvantage appears to derive from the fact that the stiffened portions of the slide fastener have relatively sharp corners and edges and, when the slide fastener is stitched into a garment, cause scratching and irritation of the user.

It is, therefore, the principal object of the present invention to provide improved endstop arrangements for slide fasteners and a method of making such slide fasteners which will extend the principles originally set forth in the aforementioned copending applications and will avoid the specific disadvantages enumerated.

Another object of this invention is to provide an improved slide-fastener construction whereby the endstop members may be molded at least in part from an applied reinforcing strip or foil but scratching and irritation of the user of the slide-fastener is avoided and attachment of the slide fastener to a garment or other support is facilitated.

These and other objects, which will become apparent hereinafter, are attained, in accordance with my present invention, with an improved slide fastener constituting a departure from prior arrangements in that the reinforcing foil extends only over a fraction of the width of the slide-fastener strip. Thus, I have discovered, notwithstanding earlier views universally held in the field to the effect that the transverse strengthening of the slidefastener strip required the foil to extend the full width of the slide fastener, that scratching of the user can be entirely eliminated without increasing the tendency toward deterioration of the slide fastener and, indeed, the

useful life of the slide fastener can be extended by improving the manner in which it is stitched to its support, when, along the edge of each tape remote from the respective coupling element in the region of the reinforcing strip, a marginal nonreinforced portion is left. The stitching of the respective slide-fastener halves to their supports via these tapes is effected along these marginal portions beyond the reinforcing foil. Furthermore, the foil corners are inwardly of the outer boundaries of the slide-fastener strip, thereby ensuring that they will not irritate the wearer of a garment to which the slide fastener is affixed.

Even more surprisingly, it is found that, when the thermoplastic foil of limited width is bonded to the slidefastener strip under heat and pressure and the endstop formations are molded from the material of the thermoplastic coupling element and/or the foils, the lateral strength of the slide-fastener halves and resistance to separation of the coupling elements and/or stop formations from the tape at the extremities of the coupling elements is approximately equal to those of slide fasteners in which the reinforcing foil spans the entire breadth of the tape.

I have discovered, moreover, that best results are obtained when the width of each of the endstop members from the foil on the respective slide-fastener portion is approximately one half the width of the tape and, correspondingly, the total length of the foil applied to the tape is approximately one-half the width of the continuous slide-fastener strip. Even with a coverage of such limited proportions, the transverse strength, tear resistance and bending resistance of the reinforced extremity of the slide-fastener half is approximately equal to thatobtainable with the earlier-disclosed reinforcing foils spanning the entire width of the slide fastener. It has also been found to be important that longitudinal extent of the reinforcing foil or endstop member, i.e., its major dimension in the direction of the coupling elements, be at least equal to the transverse extent thereof. The surprising effectiveness of limited-area reinforcing foils of the character here described, which alleviate problems encountered with earlier reinforcing systems, can be attributed to a distribution of the transverse load or stress upon the endstop members along the length thereof parallel to the coupling elements. The corners or ends of the foils, after their emplacement upon the respective slidefastener halves, need no longer be cut on a bias, rounded or smoothed to eliminate sharp edges whereas the longitudinal flexibility of the slide fastener, especially important when the latter is used in garments, is not materially reduced.

The above and other objects, features and advantages of the present invention will become more readily apparent from the following description, reference being made to the accompanying drawing in which:

FIG. 1 is a plan view showing a slide-fastener strip according to this invention,'prior to the severing thereof into individual slide-fastener lengths but subsequent to the emplacement of the reinforcing foils;

FIG, 2 is a cross-sectional view, somewhat enlarged taken along the line 11-11 of FIG. 1;

FIG. 3 is a cross-sectional view taken along the line IIIIII of FIG. 1; and

FIG. 4 is a view similar to FIG. 1 of a modification of the invention.

In FIGS. 1-3 of the drawing, I show a slide-fastener strip generally designated 20 whose slide-fastener halves 21 and 22 are interconnected by their respective coupling elements and are passed continuously through a fusion press in which a synthetic-resin foil is applied at spacedapart locations to the continuously moving strip 20 and molded into endstop members so that the endstop members have a volume equal to the moldable resin of the foils and of the fused portions of the synthetic-resin coupling elements merged therewith. The apparatus for this .4 purpose can be of the type described in applications Ser. Nos. 472,953 and 473,003 (i.e. US. Patent No. 3,353,- 256 and No. 3,340,594).

The slide-fastener halves 21 and 22 each have a respective textile support band or tape 1 or 2 with a respective endless coupling element 3 or 4, these elements being nterfitted as illustrated in FIG, 3. While suitable coupling elements include a train of spaced-apart coupling members formed from a synthetic resin having thermoplastic character, a helical coil is preferred as shown in FIGS. 1 and 3. The synthetic resin of the coupling elements 3 or 4 may be of the molecularly oriented type and preferably is a molecularly reoriented polyamide or polyurethane. The coupling elements 3 and 4 are joined to the respective tapes 1 or Z by conventional means here illustrated as including a weld cord or fillet 23, 24 serving as guides for the slider (not shown) and attached to the coupling elements 3, 4 and to the tapes 1, 2 by chain stitching 25, 26 (FIG. 3).

At spaced locations along the strip 20, I apply stiffening foils, as represented by the outline 27, of generally rectangular configuration and of a length L approximately equal to one-half the width W of the strip 20. Thus, the coupling members 5 and 6 on each side of the strip 20 are molded integrally from such foils 27 and can be separated by an opening 28 between the ridge-like formations 7 and 8 so that the individual members 5, 6 have widths approximating only half the width of the respective tape. The longitudinal extent w of the foil 27 preferably is equal to at least one-half L for the reason indicated earlier. The foils 27 above and below the strip 20 are applied as described in the aforementioned copending applications. They are thermally bonded to each other through the textile tapes 1, 2 and fused to the thermoplastic coupling elements 3, 4. The thickened ridges of bulging cross-sections 7 and 8 extend along the coupling elements but are provided with lateral or transverse projections 10 and 11, extending toward the respective tapes and intercepting the slide in its extreme position. When the endless strip 20 is subdivided along the line 12 into individual lengths of slide fastener, these formations 10 and 11 are located at the very extremities thereof. I have found it also advantageous to simultaneously mold formations 13 from the thermoplastic coupling elements 3 and 4 above the endstop members 5 and line 12 to enable the slider to pass onto the slide-fastener halves and to serve as guide for this purpose. After the setting of the slider, the bands 1 and 2 at the closure end are joined together by a transverse heat weld at the level of location 13 or are sewed together by a stitch seam for this purpose; the marginal portion 17 outwardly of the foil members 5 thus remains free.

In the system of FIG. 4, the width w of the band forming the endstop members 35 is greater than in the embodiment of FIG. 1 and the endstop members 37 and 38 flanking the opening 38' between the coupling elements 33 and 34 of the tapes 31 and 32 are molded from the foil as previously set forth. Marginal strips 47 are again formed outwardly of the endstop members which have lateral projections 40 and 41. A pair of guide ramps 14 and 15 are, however, molded integrally with the endstop members prior to separation along the line 16. The outwardly divergent regions 14 and 15 thus constitute plug-like members upon one of which a socket can be mounted while the other member is insertable therein through the slider (see commonly assigned application Ser. No. 562,887). In this case, the slide fastener is eifective as a separable arrangement.

It will thus be seen that I have provided a slide fastener whose supporting tapes, as particularly illustrated in FIG. 1 for the tape 1, are each provided with an unencumbered marginal fabric portion P whose width is substantially half that of the tape and which extends over the full length thereof so as to impart the desired degree of flexibility to the individual fastener half and to the fastener assembly as a whole.

I claim:

1. In a slide fastener having a pair of matingly couplable slide-fastener halves each including a flexible-fabric support tape and a respective continuous thermoplastic coupling element extending along one edge of the tape and matingly engageable with a similar coupling element of the other tape, and endstop members at least at one extremity of the slide fastener and composed of thermoplastic synthetic-resin material, the improvement wherein (a) each of said endstop members is constituted of a synthetic-resin foil of substantially uniform cross-section extending from the respective coupling element along the respective tape in thermally bonded relationship therewith while spanning about one-half the full width of the tape whereby a flexible and unencumbered marginal fabric portion having substantially half the width of said tape extends beyond each of said endstop members over the full length of the p (h) each of said endstop members has at least one formation unitarily formed from the foil and disposed along the respective coupling element for interception of a slider movable along said coupling elements;

(0) said coupling elements, endstop members and foil are monolithically fused together at said endstop members; and

(d) said tape is at least partially imbedded in the synthetic resin of said foil all along the part of the tape spanned by the foil, the synthetic resin permeating the interstices of the fabric of the tape.

2. The improvement defined in claim 1 wherein said endstop members extend longitudinally in the direction of the respective coupling elements through a distance greater than the width of the respective endstop member transverse to said coupling elements, said coupling elements are generally helical coils of a molecularly oriented synthetic resin, a pair of said foils are disposed coextensively on opposite sides of said slide fastener, and the longitudinal dimension of each foil is about equal to the transverse dimension thereof.

References Cited UNITED STATES PATENTS 3,001,904 9/1961 Porepp 24205.11 X 3,030,684 4/1962 Johns 24-205.11

FOREIGN PATENTS 112,326 10/ 1964 Czechoslovakia. 988,659 4/ 1965 Great Britain.

BERNARD A. GELAK, Primary Examiner 

